tailieunhanh - Humanoid Robots - New Developments Part 5

Tham khảo tài liệu 'humanoid robots - new developments part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 132 Humanoid Robots New Developments Fig. 4. Desired and real Moving velocity at Rp. Fig. 5. Dynamic propulsion potential and real force of the back leg along the x direction at Rp. Fig. 6. Angle and limit angle of the back leg knee. Analytical Criterions for the Generation of Highly Dynamic Gaits for Humanoid Robots Dynamic Propulsion Criterion and Dynamic Propulsion Potential 133 Single support phase During this phase we have four joint actuators to ensure the dynamic propulsion and to avoid the contact between the tip of the swing leg and the ground. In order to do this the swing leg s knee is used to avoid the contact while the three other joints perform the dynamic propulsion of the robot. The joint torque of the swing leg knee is calculated with a computed torque method using non linear decoupling of the dynamics. The desired joint acceleration velocity and position of the swing leg knee are calculated with inverse kinematics. We express the joint torque of the swing leg knee as function of the three other joint torques and of the desired control vector components of the swing leg s knee. With the three other joints we perform the dynamic propulsion. It is possible that the robot does not have the capability to propel itself along the x direction dynamically. In this case we limit the desired force with its dynamic propulsion potential. Then we distribute this desired force with the dynamic propulsion potential of each leg. In order to keep a maximum capability for each leg the desired force generated by each leg is chosen to be as further as possible from the joint actuators limits. In this case we have three equations one for the desired force along the x direction for each leg and one for the desired force around the z direction to calculate the three joint torques. The joint torque of the swing leg s knee is replaced by its expression in function of the three other joint torques. So we calculate the three joints torque performing the dynamic .